U.S. patent number 7,660,110 [Application Number 12/211,670] was granted by the patent office on 2010-02-09 for computer system with motor cooler.
This patent grant is currently assigned to Hewlett-Packard Development Company, L.P.. Invention is credited to Troy Della Fiora, John P. Franz, Jeffery M. Giardina, Wade D. Vinson.
United States Patent |
7,660,110 |
Vinson , et al. |
February 9, 2010 |
Computer system with motor cooler
Abstract
A computer system comprises a chassis, an electronic component
disposed within the chassis, and a cooling fan that comprises a
motor support fixed to a housing that is coupled to the chassis and
a hub disposed within the housing. A plurality of blades extend
radially from the hub. A motor is disposed within a motor enclosure
formed by the motor support and the hub. The hub is rotatably
coupled to the motor such that the plurality of blades generates a
flow of air around the motor enclosure. The system comprises a
motor cooler comprising a flow path through the motor enclosure,
where the flow path has a first opening and a second opening, and
where the second opening is disposed within an area of lowered
downstream pressure so as to develop a differential pressure
between the first and second openings and generate a flow of air
through the motor enclosure.
Inventors: |
Vinson; Wade D. (Magnolia,
TX), Franz; John P. (Houston, TX), Della Fiora; Troy
(Spring, TX), Giardina; Jeffery M. (Cypress, TX) |
Assignee: |
Hewlett-Packard Development
Company, L.P. (Houston, TX)
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Family
ID: |
37910498 |
Appl.
No.: |
12/211,670 |
Filed: |
September 16, 2008 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20090009962 A1 |
Jan 8, 2009 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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11247581 |
Oct 11, 2005 |
7443063 |
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Current U.S.
Class: |
361/679.47;
417/423.8; 417/368; 415/213.1; 415/175; 361/695; 361/690;
361/679.48; 310/58; 310/52 |
Current CPC
Class: |
G06F
1/20 (20130101); H02K 7/14 (20130101); F04D
25/082 (20130101); H02K 9/06 (20130101) |
Current International
Class: |
H05K
7/20 (20060101) |
Field of
Search: |
;361/690,692,694-697,679.47,715-722
;165/80.3,104.33,121,122,125,185 ;415/76,77,176,116,143,211.2,221
;416/181,93R,193A,175,203 ;417/176,360,368,423.8,353,423.1,366,354
;310/47,52,58,59,62-64,60A,67R |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Datskovskiy; Michael V
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATION
This patent application is a divisional of and claims priority to
commonly-owned, U.S. patent application Ser. No. 11/247,581 filed
Oct. 11, 2005 now U.S. Pat. No. 7,443,063, which is incorporated
herein by reference. This patent application may be related to
commonly-owned, co-pending U.S. patent application Ser. No.
12/211,659.
Claims
What is claimed is:
1. A computer system comprising: a chassis; an electronic component
disposed within said chassis; and a cooling fan disposed within
said chassis, wherein said cooling fan comprises: a motor support
fixed to a housing that is coupled to said chassis; a hub disposed
within said housing, wherein a plurality of blades extend radially
from said hub; a motor disposed within a motor enclosure formed by
said motor support and said hub, wherein said hub is rotatably
coupled to said motor such that the plurality of blades generates a
flow of air around the motor enclosure; and a motor cooler
comprising a flow path through the motor enclosure, wherein the
flow path has a first opening and a second opening; wherein the
second opening is disposed within an area of lowered downstream
pressure so as to develop a differential pressure between the first
and second openings and generate a flow of air through the motor
enclosure; wherein the first opening comprises a single aperture
through said hub and a cavity within said hub.
2. The computer system of claim 1 wherein the flow of air around
the motor enclosure passes over said electronic device.
3. The computer system of claim 1 further comprising a heat sink
thermally coupled to said electronic device.
4. The computer system of claim 1, wherein the first opening is an
inlet formed in said hub and the second opening is an outlet formed
through said motor support.
5. The computer system of claim 1, wherein the differential
pressure is developed between the first opening and the second
opening by the flow of air around the motor enclosure.
6. The computer system of claim 1, wherein the second opening is in
fluid communication with the flow of air around the motor
enclosure.
7. The computer system of claim 1, wherein the second opening is in
fluid communication with a contraction in the flow of air around
the motor enclosure.
8. The computer system of claim 1 wherein the second opening
comprises a venturi in fluid communication with the flow of air
around the motor enclosure.
9. The computer system of claim 1, wherein the first opening
comprises: a scoop that draws air into said hub; and a dam that
forces the air through the motor enclosure.
10. A computer system comprising: means for supporting a motor
within a housing; means for connecting the housing to a computer
chassis supporting an electronic component; means for rotatably
coupling a plurality of blades to the motor; and means for cooling
the motor that utilizes an area of lowered downstream pressure
within the flow of air around the motor enclosure to generate
airflow through the motor enclosure; wherein said means for cooling
said motor comprises a venturi in fluid communication with the flow
of air around the motor enclosure.
11. The computer system of claim 10 wherein said means for cooling
said motor transfers heat from said motor into the flow of air
around the motor enclosure.
Description
BACKGROUND
Computer systems include numerous electrical components that draw
electrical current to perform their intended functions. For
example, a computer's microprocessor or central processing unit
("CPU") requires electrical current to perform many functions such
as controlling the overall operations of the computer system and
performing various numerical calculations. Generally, any
electrical device through which electrical current flows produces
heat. The amount of heat any one device generates generally is a
function of the amount of current flowing through the device.
Typically, an electrical device is designed to operate correctly
within a predetermined temperature range. If the temperature
exceeds the predetermined range (i.e., the device becomes too hot
or too cold), the device may not function correctly, thereby
potentially degrading the overall performance of the computer
system. Thus, many computer systems include cooling systems to
regulate the temperature of their electrical components. One type
of cooling system is a forced air system that relies on one or more
cooling fans to blow air over the electronic components in order to
cool the components.
The cubic feet per minute ("CFM") of air that can be moved across
an electric device is an important factor in how much heat can be
removed from the device. Thus, the capacity of a cooling fan is a
critical factor in selecting an air mover for use in a cooling
application. The CFM that a cooling fan can produce is governed a
number of factors including: the total area of the blades
generating the airflow, the free area provided for airflow through
the fan, the design of the blades, and the power generated by the
electric motor.
The electric motors used to power many cooling fans are brushless
electric motors. Brushless motors utilize a cylindrical windings
section with magnets disposed inside or outside the cylinder. As
electrical current flows through the windings, the magnets rotate
about the axis of the motor. The amount of current flowing through
the windings determines the power that the motor produces. One
limiting factor in the performance of the motor is that the heat
produced by the windings is proportional to the amount of current
flowing through the windings. Therefore, as power increases the
heat generated by the windings also increases.
Performance of the motor may be limited because as temperature
increases, efficiency and service life decrease. High temperatures
tend to degrade insulation found in the windings section and
decrease the performance of bearings supporting the rotating
components of the fan.
BRIEF DESCRIPTION OF THE DRAWINGS
For a detailed description of exemplary embodiments of the
invention, reference will now be made to the accompanying drawings
in which:
FIG. 1 shows a cooling fan constructed in accordance with
embodiments of the invention;
FIG. 2 shows a cooling fan constructed in accordance with
embodiments of the invention;
FIG. 3 shows a blade assembly constructed in accordance with
embodiments of the invention;
FIG. 4 shows a blade assembly constructed in accordance with
embodiments of the invention;
FIG. 5 shows a cooling fan constructed in accordance with
embodiments of the invention; and
FIG. 6 shows a computer system comprising cooling fans constructed
in accordance with embodiments of the invention.
NOTATION AND NOMENCLATURE
Certain terms are used throughout the following description and
claims to refer to particular system components. As one skilled in
the art will appreciate, computer companies may refer to a
component by different names. This document does not intend to
distinguish between components that differ in name but not
function. In the following discussion and in the claims, the terms
"including" and "comprising" are used in an open-ended fashion, and
thus should be interpreted to mean "including, but not limited to .
. ." Also, the term "couple" or "couples" is intended to mean
either an indirect or direct connection. Thus, if a first device
couples to a second device, that connection may be through a direct
connection, or through an indirect connection via other devices and
connections.
DETAILED DESCRIPTION
The following discussion is directed to various embodiments of the
invention. Although one or more of these embodiments may be
preferred, the embodiments disclosed should not be interpreted, or
otherwise used, as limiting the scope of the disclosure, including
the claims. In addition, one skilled in the art will understand
that the following description has broad application, and the
discussion of any embodiment is meant only to be exemplary of that
embodiment, and not intended to intimate that the scope of the
disclosure, including the claims, is limited to that
embodiment.
Referring now to FIG. 1, cooling fan 100 comprises outer housing
10, motor 20, blade assembly 30, and motor cooler 40. Outer housing
10 comprises outer wall 12, struts 14, and motor housing 16. Motor
20 comprises windings section 22, axle 24, bearings 25, and magnets
26. Blade assembly 30 comprises a plurality of blades 34 extending
from a hub 32 that is connected to axle 24. Motor cooler 40
comprises inlet openings 42 in hub 32, flow paths 44 through
windings section 22, and outlet openings 46 in motor housing 16.
Motor housing 16 and hub 32 form a motor enclosure 50 that
substantially surrounds motor 20.
As current is supplied to windings section 22, blade assembly 30
rotates such that blades 34 generate a flow of air through housing
10 and around motor enclosure 50. As the velocity of air moving
through housing 10 increases, the air pressure decreases creating
an area of lowered downstream pressure. Outlet openings 46 are
disposed within this area of lowered downstream pressure. Thus,
when air is flowing through housing 10, the air pressure P1
proximate to inlet openings 42 is greater than the air pressure P2
proximate to outlet openings 46. This pressure differential draws
air into inlet openings 42, through flow paths 44, and to outlet
openings 46. Once the air passes through outlet openings 46 it
mixes with the airflow that traveled around motor enclosure 50 and
exits housing 10.
Motor cooler 40 thus generates a flow of air through motor
enclosure 50. This flow of air passes directly over windings
section 22. As the air passes over windings section 22, heat
generated by the windings section is transferred to the air. This
heat transfer decreases the temperature of windings section 22. By
decreasing the temperature of windings section 22, motor cooler 40
may allow motor 20 to be operated at a higher power. The airflow
across motor 20 also helps to reduce the temperature of bearings 25
and may reduce the degradation of grease used in the bearings and
may allow for the use of lower cost bearings and grease. Thus,
reducing the temperature of bearings 25 may increase the life and
performance of the bearings. Reducing the temperature of motor 20
also potentially improves the useful life of the motor by reducing
the thermal loads on the motor.
Referring now to FIG. 2, cooling fan 200 comprises outer housing
110, motor 120, blade assembly 130, and motor cooler 140. Struts
114 project inward from wall 112 of outer housing 110 and support a
motor housing 116. Struts 114 form contractions 118 in the airflow
where the velocity of the air increases. Contractions 118 may be a
venturi, restriction in the flow path, or other feature that
decreases pressure by increasing flow velocity. Motor 120 comprises
windings section 122, axle 124, and magnets 126. Blade assembly 130
comprises a plurality of blades 134 extending from a hub 132 that
is connected to axle 124. Motor housing 116 and hub 132 form a
motor enclosure 150 that substantially surrounds motor 120. Motor
cooler 140 comprises inlet openings 142 in hub 132, flow paths 144
through windings section 122, and outlet passages 146 in fluid
communication with contractions 118.
As air passes through contractions 118, the velocity of the air
increases and the pressure decreases creating an area of lowered
downstream pressure. Outlet passages 146 are disposed within this
area of lowered downstream pressure. Thus, when air is flowing
through housing 110, the air pressure P3 proximate to inlet
openings 142 is greater than the air pressure P4 proximate to
outlet passages 146. The pressure differential between P3 at inlets
142 and P4 at outlets 146 draws air through flow paths 144.
Contractions 146 may be formed by struts 114, or on other features
found within housing 110, such as stator vanes or wire guides.
Referring now to FIG. 3, a blade assembly 300 comprises hub 302,
blades 304, scooped apertures 306, and air dams 308. Blade assembly
300 can be used with either of the motor cooling systems above or
can be used independently so as to generate an airflow over a motor
that is disposed in line with, and downstream from, the blade
assembly. As blade assembly 300 is rotated, scooped apertures 306
pull air into the interior of hub 302. Air dams 308 then redirect
the air axially from hub 302 toward a motor in line with blade
assembly 300. The scooped apertures 306 and air dams 308 cooperate
to further increase the air pressure near the hub to allow for a
greater pressure differential and therefore increased airflow
through the motor housing.
Referring now to FIG. 4, a blade assembly 400 comprises hub 402,
blades 404, a single aperture 406, and chambers 408. Blade assembly
400 can be used with either of the motor cooling systems above or
can be used independently so as to generate an airflow over a motor
that is disposed in line with, and downstream from, the blade
assembly. As blade assembly 400 is rotated, air enters chamber 408
through aperture 406. Chambers 408 allow airflow expansion and
mixing before the air moves across an adjacent motor. Single
aperture 406 minimizes penetrations through hub 402, thereby
preserving the strength of the hub.
Referring now to FIG. 5, cooling fan 500 comprises outer housing
510, motor 520, and blade assembly 530. Outer housing 510 comprises
outer wall 512, stators or struts 514, and motor housing 516. Motor
520 comprises windings section 522, axle 524, and magnets 526.
Blade assembly 530 comprises a plurality of blades 532 extending
from a hub 534 that is connected to axle 524. Stators 514 and motor
housing 516 are thermally coupled, such as by over-molding a
thermally conductive material onto windings section 522 or
disposing a thermally conductive material between stators 514 motor
housing 516. In certain embodiments, stators 514 may comprise, or
be thermally coupled to, other heat transfer elements, such as heat
pipes, vapor chambers, or liquid cooling systems that dissipate
heat from motor 520. This assembly creates a thermal conduit that
transfers heat from windings section 522 into stators 514, which
are disposed within the air flow generated by blade assembly
530.
Referring now to FIG. 6, a computer assembly 600 comprises chassis
602, motherboard 604, heat sinks 606, electronic components 608,
and cooling fans 610. Each cooling fan 610 comprises a housing 612
surrounding a blade assembly 614 that is rotated by an electric
motor that is cooled by a motor cooler 616. Cooling fans 610 are
arranged so as to generate an airflow that cools electronic
component 608. Heat sinks 606 may be arranged so as to be directly
in the airflow generated by fans 610. Heat sinks 606 are coupled to
electronic components so that the heat generated by the electronic
component is dissipated to the airflow through the increased
surface area of the heat sink.
The above discussion is meant to be illustrative of the principles
and various embodiments of the present invention. Numerous
variations and modifications will become apparent to those skilled
in the art once the above disclosure is fully appreciated. For
example, the openings into the motor housing may be arranged such
that the airflow across the motor flow in a direction opposite the
flow generated by the fan blades. It is intended that the following
claims be interpreted to embrace all such variations and
modifications.
* * * * *